Add libomptarget discovery to prevent OpenMP/HIP segfaults (#1043)

This PR fixes a segmentation fault seen when running rocprof-sys-sample with multi-process OpenMP/HIP applications.
The crash was caused by missing libomptarget.so on the runtime loader path or incorrect LD_PRELOAD settings.

Fixes SWDEV-552804

---------

Co-authored-by: David Galiffi <David.Galiffi@amd.com>

projects/rocprofiler-systems/source/bin/rocprof-sys-causal/impl.cpp

@@ -204,6 +204,14 @@ get_initial_environment()
                get_env<int>("ROCPROFSYS_THREAD_POOL_SIZE", 0));
     update_env(_env, "ROCPROFSYS_LAUNCHER", "rocprof-sys-causal");
 
+    // Ensure libomptarget.so can be found by the target (OpenMP/HIP apps)
+    if(auto llvm_dir =
+           rocprofsys::common::discover_llvm_libdir_for_ompt(get_verbose() > 0);
+       !llvm_dir.empty())
+    {
+        update_env(_env, "LD_LIBRARY_PATH", llvm_dir, /*append=*/true);
+    }
+
     return _env;
 }
 
@@ -351,13 +359,13 @@ update_env(std::vector<char*>& _environ, std::string_view _env_var, Tp&& _env_va
                     if(_env_var == "LD_PRELOAD")
                     {
                         itr =
-                            strdup(join('=', _env_var, join(_join_delim, _val, _env_val))
+                            strdup(join('=', _env_var, join(_join_delim, _env_val, _val))
                                        .c_str());
                     }
                     else
                     {
                         itr =
-                            strdup(join('=', _env_var, join(_join_delim, _env_val, _val))
+                            strdup(join('=', _env_var, join(_join_delim, _val, _env_val))
                                        .c_str());
                     }
                 }